Title. When I change the cost of a single OSPF link from a ost of 2 to 1, it breaks R3. I'm talking about the link between R3 and R4. IS there anything in the config I should change? All of the OSPF settings are left at default and I'm using /30 links between each router.

I should add that the Edgemax infiniti is my BGP client and is the way out.

Setup: